Acta Phys. -Chim. Sin. ›› 2000, Vol. 16 ›› Issue (01): 70-75.doi: 10.3866/PKU.WHXB20000114

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Phase Diagrams of Na2CrO4-(NH4)2CrO4-H2O System

Cui Jin-Lan, Zhang Yi, Liu Chang-Jian   

  1. Institute of Chemical Metallurgy,Chinese Academy of Sciences,Beijing 100080
  • Received:1999-03-09 Revised:1999-05-12 Published:2000-01-15
  • Contact: Cui Jin-Lan


The phase diagrams of Na_2CrO_4- (NH_4)_2CrO_4-H_2O system at 20℃ and 50℃ have been determined by solubility method. The experimental results have also been verified by mathematical method. The phase diagrams show that there is a double salt of NaNH_4Cro_4• 2H_2O formed in the system, which will decrease the purity of (NH_4)_2CrO_4 Consequently, a method is found to separate the fixture of ammonium chromate and double salt by analysing the phase diagrams.

Key words: Phase diagram, Separation, Ammonium chromate, Double salt